边界条件:x=0时:w=0→B=0 x=时:w=0→Asin=0 sink=0→k=nx(n=0,1,2,…) k-nn b→F=hxE 2 k 2 El CL13tU6sin kl = 0 边界条件：x = 0时：w = 0  B = 0 x = l时：w= 0  Asinkl = 0  kl = n (n = 0,1,2, ) k n l =  2 2 2 l n EI F   = EI F k = 2 EI F = CL13TU6